نتایج جستجو برای: catalyst reusability
تعداد نتایج: 48764 فیلتر نتایج به سال:
zrp2o7 nanoparticles have been used as an efficient catalyst for the preparation of 2-aryl-5-methyl-2,3-dihydro-1h-3-pyrazolones by a simple one-pot four-component reaction of phenyl hydrazines, ethyl acetoacetate ,β-naphthol and benzaldehydes under microwave irradiation in good to excellent yields. when the reaction was carried out using zrocl2.8h2o, zro2 and zrp2o7 nps as the catalyst, the pr...
the fe-mcm-22 zeolite was found to be an efficient solid heterogeneous catalyst for synthesis of dihydropyrano [2,3-c] pyrazoles via one pot four component reaction of ethyl acetoacetate, hydrazine hydrate, aromatic aldehyde and malononitrile in aqueous alcohol. the catalyst was synthesized by hydrothermal method under autogenous pressure and modified by fe (iii) ion exchange. the prepared cata...
an efficient, simple and convenient route is described for the synthesis of biscoumarin (3,3'-(arylmethylene) bis (4-hydroxy-2h-chromen-2-one)) by using of recyclable catalyst tio2@ksf. in this method, we synthesis biscoumarin derivatives via 3multi-component reactions (3mcrs) of two equivalent 4-hydroxycoumarin with one equivalent of aromatic aldehydes using 20 mg nano tio2@ksf as homogen...
Synthesis of 2,4,5-triaryl-1H-imidazoles using a potent, green and reusable nano catalyst (FHS/SiO2)
A simple, green and efficient method for synthesis of 2,4,5-trisubstituted imidazoles is described via three-component cyclocondensation of benzil or benzoin, aldehyde and ammonium acetate by using the nano SiO2-supported ferric hydrogen sulfate (FHS/SiO2), as a catalyst, under solvent-free conditions. The nano SiO2 support and catalyst were characterized by X-ray diffraction (XRD), transmissio...
this study introduces a green and efficient method for preparation of biologically-active substituted 4h-pyrans using the one-pot three-component reaction of aromatic aldehydes, dimedone and malononitrile in the presence of cobalt oxide nanoparticles. co3o4 nanoparticles were used as an efficient catalyst for the synthesis of polyhydroquinoline derivatives by the reaction of aromatic aldehydes,...
Nano TiO2 supported on SiO2 (Nano TiO2@SiO2) as a solid Lewis acid, was described to be an effective and reusable catalyst for one-pot three-component reaction of benzil, aryl aldehydes and ammonium acetate for the synthesis 2-aryl-4,5-diphenyl-1H-imdazoles synthesis. To explore the high efficacy of the catalytic system the four-component cyclization of benzil, aryl aldehydes, ammonium acetate ...
a series of 2-amino pyridine-3-carbinitrile derivatives incorporated coumarin moiety has developed via multicomponent condensation of 3-acetyl-2h-chromen-2-one, arylaldehydes, malononitrile and ammonium acetate utilizing brønsted acidic ionic liquid, (4-sulfobutyl)tris(4-sulfophenyl)phosphonium hydrogen sulfate as catalyst under solvent-free conditions. good yields, short reaction times, straig...
Nanocrystalline alumina powder has been synthesized using solution combustion method. The obtained nanocrystalline alumina powder was used as an efficient catalyst for the synthesis of imidazo[1,2-a]azine derivatives from one-pot three component reaction of benzaldehyde, 2-aminoazine and trimethylsilylcyanide under ultrasonic irradiation and refluxing condition. Reusability of catalyst and shor...
Heterogeneous transesterification of vegetable oils offers an environmentally more attractive option for biodiesel production compared with the conventional homogeneous processes. Thus, double metallic methoxide catalyst was developed in the present study, aiming to improve the transesterification of low-cost palm stearin (PS) and reduce waste generation. The physicochemical properties of the s...
Novel multi-SO3H functionalized strong Brønsted acidic ionic liquid coated magnetite nanoparticles have been prepared and applied as catalyst for the synthesis of 2,4,5-trisubstituted imidazoles. The results showed that a novel catalyst was very efficient for the reaction and could be magnetically separated and reused at least 6 times with less reduction in its catalytic activity. Operational s...
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